Manganese neodecanoate

Endpoint summary

Description of key information

Aquatic toxicity data of manganese neodecanoate are not available. Read-across to the assessment entities soluble manganese substances and neodecanoic acid is applied for the assessment of manganese neodecanoate since the ions of manganese neodecanoate determine its fate and toxicity in the environment. Reliable data available for soluble manganese substances and nedecanoate indicate that the moiety of ecotoloxicological concern are manganese cations though manganese is an essential trace nutrient.

Manganese

Manganese cations, even though essential, appear to be toxic to fish, invertebrates and algae. The lowest respective acute effect concentrations of manganese for fish, invertebrtaes, algae and microorganisms are as follows:

-96-h LC50 of 3.17 mg Mn/L for Oncorhynchus mykiss

-96-h LC50 of 3.0 mg Mn/L for Hyalella azteca

-72-h ErC50 of 19.8 mg Mn/L for the inhibition of growth rate of Desmodesmus subspicatus

-3-h EC50 of > 325.1 mg Mn/L for respiration inhibition of aquatic microorganisms

 

The lowest respective long-term (chronic) effect concentrations for fish, invertebrtaes, algae and microorganisms are as follows:

- 4-months NOEC/EC10 of 0.6 mg Mn/L for Oncorhynchus mykiss

- 60-d NOEC of 0.01 mg Mn/L for Macrobrachium rosenbergii (giant river prawn)

- 72-h NOErC of 0.325 mg Mn/L for the inhibition of growth rate of Desmodesmus subspicatus

- 3-h NOEC of 182 mg Mn/L for respiration inhibition of aquatic microorganisms

For marine aquatic species, the lowest identified endpoint is a NOEC of 0.02 mg Mn/L.

Neodecanoic acid

Reliable acute data are available from GLP-conform guideline studies for three trophic levels: algae, invertebrates and fish

- an unbounded value of > 100 mg/L (96h-LL50) was identified for rainbow trout

- an unbounded value of > 457 mg/L (48h-EL50) was identified for the invertebrate species Daphnia magna

- an unbounded value of > 100 mg/L (72h-LL50) was identified for the algae Pseudokirchneriella subcapitata

 

Reliable chronic data are available from GLP-conform guideline studies for two trophic levels: invertebrates and fish

- 21-d NOEC of 4.78 mg/L neoheptanoic acid (structural analogue) for reproduction of D. magna; Chronic Value (ChV) of 1.7 mg/L (QSAR-based estimate) for daphnids

- 14-d NOEC of 2.22 mg/L neodecanoic acid for growth of Oncorrhynchus mykiss; Chronic Value (ChV) of 1.6 mg/L (QSAR-based estimate) for fish

- Regarding algae, an EC10 or NOEC is not available for neodecanoate. However, based on the fact that the EC50 for growth rate of algae is > 100 mg/L, we may assume that it is unlikely that the EC10/NOEC < 1 mg/L. According to the QSAR-based outcome of the model ECOSAR v.2.0, neodecanoic acid has a very low potential for chronic toxicity to green algae since the chronic value (ChV = 10^([log (LOEC x NOEC)]/2)) of 12.3 mg/L is >> 1 mg/L.

 

Regarding the toxicity to aquatic microorganisms, a 4-h NOEC of ≥ 200 mg/L for the inhibition of nitrification by microorganisms (Nitrosomonas sp.) is available.

 

In sum, neodecanoic acid has very low potential for acute aquatic toxicity and a low potential for chronic toxicity.

Manganese neodecanoate

Acute effect concentrations of manganese conservatively recalculated for manganese neodecanoate based on a maximum manganese content of 15% are as follows:

- 96-h LC50 of 21.1mg/L for Oncorhynchus mykiss

- 96-h LC50 of 20.0 mg/L for Hyalella azteca

-72-h ErC50 of 132.0 mg/L for the inhibition of growth rate of Desmodesmus subspicatus

-3-h EC50 of > 2167.3 mg/L for respiration inhibition of aquatic microorganisms

 

Chronic effect concentrations of manganese conservatively recalculated forfatty acids, tall-oil, manganese salts based on a maximum manganese content of 9% are as follows:

- 4-months NOEC/EC10 of 4.0 mg/L for Oncorhynchus mykiss

- 60-d NOEC of 0.07 mg/L for Macrobrachium rosenbergii (giant river prawn)

- 72-h NOErC of 2.2 mg/L for the inhibition of growth rate of Desmodesmus subspicatus

- 3-h NOEC of 1213.3 mg/L for respiration inhibition of aquatic microorganisms

For marine aquatic species, the lowest identified endpoint is a NOEC of 0.13 mg Mn/L.